1. Field of the Invention
This invention generally relates to a bicycle derailleur. More specifically, the present invention relates to a bicycle derailleur having a gear shifting operation that is easy to operate.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. The various components of the bicycle are usually mounted to the bicycle frame. Some components of the bicycle that have been extensively redesigned are the bicycle derailleurs.
One component that is mounted to the bicycle frame is the front derailleur. Generally speaking, the front derailleur is typically secured to the seat tube of the bicycle frame. Basically, the front derailleur includes a fixed member nonmovably secured to the seat tube of the bicycle frame, and a movable section supported to be movable relative to the fixed member. The movable section supports a chain guide having a pair of vertical surfaces for contacting a chain.
Many prior art derailleurs and their shifting devices suffer from several disadvantages. For example, most mechanical shifting devices for derailleurs require one lever or button to up shift and another lever or button to down shift. Thus, the rider can be confused on which lever or button to use. Moreover, some prior art derailleurs and/or their shifting devices are sometimes complicated and expensive to manufacture. Also the shifting devices for some require a considerable amount of force to operate.
In view of the above, there exists a need for a bicycle derailleur which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
One object of this invention is to provide riders with a gear shifting operation that is easy to operate. The shifting of the derailleur, either from a low gear to a high gear or vice versa, requires only to push a shifting lever. This push forces the rotating cam to only rotate in one direction.
Another object is to provide a gear shifting mechanism that is simple and low cost to produce.
Yet another object is to provide a gear shifting operation that is very light to operate.
The foregoing objects can basically be attained by providing a derailleur for a bicycle is provided that is easy to operate. The derailleur basically has a mounting member, a chain guide and a chain guide positioning mechanism. The mounting member is adapted to be coupled to a portion of the bicycle. The chain guide is movably coupled to the mounting member. The chain guide is adapted to shift a chain of a bicycle in a transverse direction. The chain guide positioning mechanism has an actuating cam operatively coupled to the chain guide. The actuating cam is adapted to be coupled to a control element and is arranged to rotate only in one direction in response to movement of the control element to move the chain guide from a first position to a second position.